On 19 April 2014, an Embraer 190 (F-HBLF) being operated by Régional on a scheduled domestic passenger flight from Paris CDG to Clermont-Ferrand Auvergne had completed an uneventful daylight push back and engine start in normal ground visibility but as the planned pull-forward was commenced, the tow bar connection broke and the aircraft collided with the tug causing "severe damage to the lower part of the fuselage". There were no injuries to those on the aircraft or the ramp.
An Investigation into the collision was carried out by the BEA France.
It was established that after the Apron Management Services Agent (AMSA) had asked them to push back facing east, the aircraft crew had called the appropriate GND frequency to request permission to pushback from their stand J10 at Terminal 2G (see the illustration below).
The stand layout at Terminal 2G. [Reproduced from the Official Report]
The crew of the aeroplane parked at J11 then also requested pushback so in order to allow this aircraft to begin its departure sooner, the AMSA then asked the crew of F-HBLF to have the attached tug tow the aircraft forward to the south after completing the initial pushback until it was abeam stand 12. After completion of the pushback, during which both engines were started, the aircraft was first positioned on the "pushback axis" associated with the gate (see the detail illustration below) and designated in the applicable Airport Procedures. The requested pull forward along taxiway E7 to abeam stand 12 in order to facilitate the aircraft on stand J11 required the tug driver to tow the aircraft through a sharp 90° right turn. To achieve this turn, he positioned his tug at approximately 90° to the aircraft axis but when he began the tow, "the safety cotter pins on the tow bar coupling head broke" which left the coupling head connected to the tow bar by only an axle around which it was able to pivot horizontally. As a consequence, "under the effect of its inertia and the thrust of the two engines at idle", the aircraft continued ahead without turning and when the coupling head reached the stop, the aircraft pivoted to the right and collided with the tug.
Detail of the stands in the vicinity of the collision site showing daytime ground lighting. [Reproduced from the Official Report]
The Investigation found that the applicable Airport Authority Instructions covering stand J10 stated that ‘‘in accordance with instructions from ATC and validation by the aircraft Captain’’, the pushback must be carried out one of two ways, either a "simple" push onto the specific axis line painted in white facing east or pushed directly from the stand to the junction of taxiways E7 and P4 (see the first illustration above) and then turned to the left so that the aircraft faces west on P4. It was found that the second option was "little used" notably because of the length of the pushback. These instructions were found to state explicitly that "it is forbidden to pull the aeroplane forward again with the aid of a tug" and such a departure along taxiway E7 must be made by the aircraft under its own power. It was noted that these Airport Authority Instructions had been developed in conjunction with the ANSP and "then distributed to airlines, runway service companies and the ANSP”. It was also noted that the Operations Manual used by the Apron Management Service "repeats the same instructions as well as the ban on 'push-pull' departures from stand J10". However, it was noted that such a 'push-pull' procedure is "authorised and regularly used at other stands on the apron in order to facilitate the flow of traffic and avoid jet blast in case of simultaneous pushbacks". It was noted that in these operations on other stands, the tug is usually aligned with the aircraft axis when any pull forward is commenced, "which limits the risks of tow bar safety cotter pin failure". It was also found that "generally speaking" drivers did not question requests such as the one which preceded the investigated collision from Apron Management Service Agents, "even if they are aware of the ban in the Operations Manual".
The Investigation discovered that the origin of the 'push-pull' from J10 had been in 2008 when it had been the approved procedure when the then new Terminal opened. Just two months into operations there, a tug/aircraft collision like the 2014 one had occurred and in response, the Airport Authority had promptly changed the prescribed J10 tug operation to push only, with aircraft permitted to move forward after the initial pushback only under their own power. The following year, another similar event of push-pull collision had occurred and an explicit warning that pull-forward was banned for J10 departures had been appended to the revised instruction.
In the investigated case, it was concluded that the issue of an Apron Management Services request which was contrary to an established and properly documented instruction should be seen in the context of "the common use of this manoeuvre at the other stands and the absence of any explanation of the reasons for the ban at that specific stand".
Safety Action: The Apron Management Services Operations Manual was modified to make the reasons for the J10 pull forward ban clear whilst the Investigation was in progress.
The Final Report was completed in September 2016. No Safety Recommendations were made.